1. Field of the Invention
The present invention relates to an automotive dynamoelectric machine that is mounted to a vehicle engine, and particularly relates to a construction of a heatsink that is mounted to a heat-generating element and that effectively radiates heat that is generated by the heat-generating element.
2. Description of the Related Art
Conventional automotive dynamoelectric machines include: a case that is constituted by a front bracket and a rear bracket that are made of aluminum; a shaft that is rotatably disposed in the case by means of bearings; a rotor that is fixed to the shaft and accommodated inside the case; fans that are fixed to two end surfaces of the rotor; a stator that is fixed to an inner wall surface of the case so as to surround the rotor; slip rings that are fixed to a rear end of the shaft and that supply electric current to the rotor; a pair of brushes that are disposed inside the case so as to that slide on the slip rings; a brush holder that houses the brushes; a rectifier that is electrically connected to the stator and that rectifies alternating current that is generated in the stator into direct current; a heatsink that is mounted to the brush holder; and a regulator that is fixed adhesively to the heatsink and that adjusts magnitude of an alternating voltage that is generated in the stator (see Patent Literature 1, for example).
Now, the rectifier and the regulator constantly generate heat while the dynamoelectric machines is generating electricity. For this reason, the heatsink is formed such that a plurality of thin plate-shaped fins are arrayed so as to project from a rear surface of a base surface, and the rectifier and the regulator are mounted to that base surface.
The rotor is driven to rotate when the dynamoelectric machine is operating. The fans are rotated together with the rotation of the rotor, generating a cooling airflow. The cooling airflow that is generated by the fans is passed through the heatsink. The cooling airflow passes through between the fins, and heat is exchanged between the fins and the cooling airflow, removing heat that is generated by the rectifier and the regulator. Thus, temperatures of the rectifier and the regulator are kept constant, and the dynamoelectric machine operates normally.
[Patent Literature 1]: Japanese Patent No. 3527516 (Gazette)
In conventional automotive dynamoelectric machines, the rectifier and the regulator are cooled using a heatsink. Improving heat radiating characteristics per unit area of the heatsink leads to stabilization of the operation of the dynamoelectric machine, and also contributes to reductions in the size of the heatsink, and thus to reductions in the size of the dynamoelectric machine.
However, because the heatsink is formed by arraying a large number of thin plate-shaped fins on the rear surface of the base surface, there has been a limit to improving heat radiating characteristics due to constraints on machining the fins.